Micro Forests: An Emerging Climate Hero?

Summary

Short Wave Podcast Summary

Episode: Micro Forests: An Emerging Climate Hero?
Date: January 7, 2026
Hosts: Emily Kwong and Regina Barber (Regina not present in this episode)
Producer/Reporter: Rachel Carlson
Guest Experts: Dr. Damian Wollett (Biologist, Loyola Marymount University), Katherine Pokradouni (Horticulturist)

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Overview:

This episode explores the concept of "microforests," small, densely planted, human-designed forests in urban environments. Producer Rachel Carlson visits a Los Angeles microforest to uncover how these mini-ecosystems could help cities combat climate change, restore biodiversity, and connect people to nature.

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Key Discussion Points & Insights

What is a Microforest? (00:13–02:22)

• Microforests are small-scale, human-engineered forests designed for dense urban spaces.
• Unlike natural forests, they are intentionally planted and use native species tailored to local environments.
• Size: Can range from about 200 square feet up to an acre. The featured L.A. microforest covers 10,000 square feet—the largest in California.

Quote:

“When you plant one tree, that's just a tree. But once you start having the canopy connect, that starts to be what we imagine as a forest.”
— Dr. Damian Wollett (01:36)

• Microforests mimic natural forests with trees whose canopies touch and distinct layers (canopy, shrubs, ground cover).

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Origins and Global Spread (04:47–05:11)

• Microforests have roots in Japan, where ecologist Dr. Akira Miyawaki developed this approach more than 50 years ago to restore degraded land.
• The practice has since spread worldwide, including Europe and the U.S.

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How to Plant a Microforest (05:11–05:44)

• Diverse species are planted densely and all at once, simulating an entire ecosystem rather than waiting for natural succession.
• Different plant heights and layers are deliberate—the lower layers enhance soil health, while dense growth encourages faster maturity (decades vs. centuries).

Quote:

“You’re kind of planting a whole ecosystem at one time... planting the whole forest at one moment.”
— Dr. Damian Wollett (05:33)

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The Los Angeles Microforest: Live Science Experiment (06:16-08:17)

• The LA microforest is two years old and used for scientific experiments.
• Adjacent to it is a control plot (same size, invasive weeds, no intentional planting) for comparison.
• Researchers monitor which animals, insects, and plants appear in each plot.
• Around 100 animal species have been observed in the microforest—matching the total previously recorded in the whole park.

Quote:

“Every two weeks… counting how many insects we're finding, what birds are there, what lizards are moving through there.”
— Dr. Damian Wollett (07:42)

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Innovative Biodiversity Research Methods (08:17–10:14)

• Each plant is mapped with a GPS coordinate; drones are used to track plant growth and health.
• Spider webs are collected and analyzed for environmental DNA (eDNA), revealing which animals (even elusive ones like owls and bats) have passed through.

Memorable Moment:

“Spider webs are kind of a filter for the air. And as animals move through … they're shedding skin cells... that sticks to the spider web...”
— Dr. Damian Wollett (08:57)

• Community scientists, via a custom mobile app, contribute data by scanning QR codes on plants to track their growth and health.

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Rapid Growth & Community Impact (10:39–11:11; 13:00–13:17)

• Some trees have outpaced similar specimens outside the microforest—a Southern California black walnut grew taller in two years than Damian’s backyard tree did in nearly a decade.
• Over 89% of the plants have survived since planting.

Memorable Moment:
Rachel notes Damian hugging one of the trees:

“He actually hugged the tree at one point, which was maybe my favorite part of the whole day.”
— Rachel Carlson (11:11)

• Visitors are engaged and interested. Several ask questions and express enthusiasm for the microforest as a space for both wildlife and people.

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Ecosystem Services & Climate Benefits (11:47–12:52)

• Dense planting crowding out weeds has reduced invasive species by ~80% in two years, compared to the control plot.
• The microforest currently sequesters about one metric ton of carbon per year—anticipated to grow to over 50 metric tons within 20 years (roughly the annual emissions from 10 SUVs).

Quote:

“It’s cooling the neighborhood. It's providing food, again, the insects, the wildlife that's here.”
— Dr. Damian Wollett (12:52)

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Notable Quotes & Timestamps

• What Makes a Forest a Forest
  “When you plant one tree, that's just a tree. But once you start having the canopy connect, that starts to be what we imagine as a forest...”
  — Dr. Damian Wollett (01:36)

• Planting a Whole Ecosystem
  “You’re kind of planting a whole ecosystem at one time. Instead of waiting for nature to kind of go through succession...”
  — Dr. Damian Wollett (05:33)

• Spiderweb Science
  “Spider webs are kind of a filter for the air... we collected spiderwebs and... used genetic tools.”
  — Dr. Damian Wollett (08:57)

• Excitement for Rapid Growth
  “He actually hugged the tree at one point, which was maybe my favorite part of the whole day.”
  — Rachel Carlson (11:11)

• Climate Mitigation
  “His lab expects that to increase to over 50 metric tons of carbon dioxide per year in the next two decades. And that's more than the emissions of 10 SUVs.”
  — Rachel Carlson (12:49)

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Important Timestamps

• Explanation of Microforests: 00:13–02:22
• Origins & Miyawaki Method: 04:47–05:11
• Dense Layered Planting Discussion: 05:11–05:44
• LA Microforest Field Visit & Biodiversity: 06:16–08:17
• Spider Web DNA Analysis: 08:52–10:14
• Community Science and Rapid Tree Growth: 10:39–11:11
• Weed Suppression & Carbon Capture: 11:47–12:52
• Human Impact and Neighborhood Cooling: 12:52–13:17

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Tone and Style

• Lively, curious, and accessible—maintaining a balance of scientific depth and everyday language.
• Moments of light-heartedness, like gentle jokes about “master gardeners” or “for the love of microforest” (13:17).
• Direct engagement with researchers gives the episode a personal, on-the-ground feel.

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Takeaway

Microforests are emerging as a dynamic climate solution—boosting urban biodiversity, fostering community involvement, and sequestering carbon. The LA microforest experiment suggests even small slices of forest can have a big impact on both environment and community, providing a hopeful model for climate adaptation in cities.

Transcript

[Emily Kwong]

This message comes from Mint mobile. Starting at $15 a month, make the [e-mail] Switch $45 upfront payment for three months. 5 gigabyte plan equivalent to $15 a month.

[Rachel Carlson]

Taxes and fees.

[Emily Kwong]

Extra first three months only. See terms. You're listening to Short Wave from npr. Hey, shortwavers. Emily Kwong here. And today I have a treat for you. We are going to a microforest. If you've never heard of one, they are small. They. And unlike natural forests, microforests are designed entirely by humans for urban environments. And producer Rachel Carlson went to visit one in Los Angeles recently. Hey, Rachel.

[Rachel Carlson]

I did. Hey. It was amazing. I had the most fun day ever. I hung out with two scientists who've dedicated themselves to planting these tiny forests to cool down cities and make them more resilient to climate change.

[Emily Kwong]

Okay, where did you go to see a microforest?

[Rachel Carlson]

Ascot Hills park, which is a park in northeast Los Angeles. It's surrounded by freeways and interstates, not too far from the heart of downtown la. So it's not really an area that I typically associate with lots of green space.

[Damian Wollett]

But you pull off the freeway and drive this way, and you see a green stamp of 10,000 square feet, and.

[Rachel Carlson]

That'S exactly what it looked like, a green stamp. That's Damien Wollett, an associate professor of biology at Loyola Marymount University. He's one of the scientists I met with who's worked on planting and maintaining this microforest for the last two years.

[Emily Kwong]

Okay, but what makes a microforest a forest?

[Rachel Carlson]

In a forest, the canopies of the trees touch one another.

[Damian Wollett]

When you plant one tree, that's just a tree. But once you start having the canopy connect, that starts to be what we imagine as a forest, where you have this kind of blockage of the sunlight. But also a forest has layers, canopies.

[Rachel Carlson]

Of trees with layers of plants beneath them. So in that way, a microforest does simulate a natural forest. Okay, but what makes a microforest micro?

[Damian Wollett]

It's smaller.

[Narrator/Advertiser]

Oh.

[Emily Kwong]

So this is not like a fairy forest with tiny plants or something. This is just a forest that's got a small footprint.

[Rachel Carlson]

Yeah, yeah. Microforests can be anywhere from around 200 square feet to an acre. And the one I visited's about a quarter acre or 10,000 square feet. But it's the largest microforest in California.

[Emily Kwong]

So did I in the show. A trip to a small forest with big dreams and real life contributions to local biodiversity that are making it easier to live with climate change. You're listening to Short Wave, the science podcast from npr.

[Narrator/Advertiser]

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[Emily Kwong]

We are talking about microforests, which are supposed to mimic natural forests, but on a smaller scale and in more URB environments.

[Rachel Carlson]

And people plant them.

[Emily Kwong]

Yeah.

[Rachel Carlson]

Ecologists use local plants to help restore biodiversity to the area. So for example, Los Angeles is prone to drought, so there's lots of drought tolerant native plants in the microforest I went to, like Southern California black walnut and blue elderberry, but in other places ecologists would use different types of plants.

[Emily Kwong]

Cool. So do microforests exist in other parts of the world?

[Rachel Carlson]

Yeah, there are others in the US And Damian, our biologist from earlier, told me they're also popular in Europe. The original idea goes back over 50 years to Japan to an ecologist named.

[Damian Wollett]

Dr. Akira Miyawaki, and he developed the idea of this kind of tiny forest approach to restoring degraded land.

[Emily Kwong]

Interesting. Well, how do you even go about planting a microforest? Like, what is involved?

[Rachel Carlson]

Well, a forest isn't just trees, it's A bunch of different species with different roles, from roots and soil to shrubs, to those tall canopy trees that you might think of when you think of a forest. So that's how microforests are planted, too, with dense layers of different kinds of plants.

[Damian Wollett]

So you're kind of planting a whole ecosystem at one time. Instead of waiting for nature to kind of go through succession step by step to get eventually to a forest, it's planting the whole forest at one moment.

[Emily Kwong]

Interesting. So why is it strategic to have plants at different heights and different layers of the forest?

[Rachel Carlson]

The lowest layers help keep the soil healthy, which ultimately keeps those upper layers growing. And planting a lot of plants all at once contributes to the microforest's growth, and they mature faster than a traditional forest. It might be a couple decades for a microforest, instead of something like a century for a bigger forest.

[Emily Kwong]

Very cool. Okay, so let's go back to the microforest you visited in la. Tell me about your field trip.

[Rachel Carlson]

My field trip?

[Emily Kwong]

Yeah.

[Rachel Carlson]

I went on a weekday at the end of November. It was warm, like 75 degrees outside.

[Emily Kwong]

Just a brisk fall day in Los Angeles.

[Rachel Carlson]

Yeah, really fun. But I pulled up to the park and met Damian, and he introduced me to someone else.

[Damian Wollett]

There's Catherine right there.

[Rachel Carlson]

Oh, great. Hey. Katherine Pokradouni is a horticulturist who helps plant and develop microforests like this one. We walked up a very steep hill to meet her. I was on a hike. You can't talk at this point because you're breathing too heavily. That's totally fine. I know my mic's gonna catch me, like, out of breath.

[Emily Kwong]

Wow. This is like meeting some master gardeners or something. But of the forest, it was. And you said that Damien and Catherine have been working on this particular microforest since 2024. So it's two years old?

[Rachel Carlson]

Yeah, they just celebrated its second birthday. And another amazing thing about a microforest compared to a much larger forest is the size allows researchers like Damien and Catherine to use it as a science experiment.

[Emily Kwong]

Yeah, you said the microforest is like a quarter of an acre?

[Rachel Carlson]

10,000 square feet. And right next to it, there's another plot of land exactly the same size, except it's brown, it's filled with invasive weeds. Catherine and Damien aren't planting anything there so they can directly compare the plots and see what kinds of insects and birds and other critters show up to each one.

[Emily Kwong]

Oh, and study the biodiversity when you create a forest with native plants.

[Damian Wollett]

Yeah, every two weeks, going back and forth between the two of them, counting how many insects we're finding, what birds are there, what lizards are moving through there. We find some cool field mice, some spiders, all sorts of neat things that we find here in the microforest that aren't over there in the control plot.

[Rachel Carlson]

All frolicking in the midst of hundreds of trees, shrubs, and other native plants they've cultivated. And Catherine and Damien have seen around 100 different animal species in all, just in the microforest, whereas prior to this.

[Damian Wollett]

Microforest being planted, we had an idea of that There were only a hundred species being documented in the whole park.

[Emily Kwong]

It's the place to be, this microforest. It's bringing the party. How are these scientists tracking the biodiversity, though? Are they walking around and counting everything?

[Rachel Carlson]

Partially, yes. They're using a few different methods, though. Damien's lab has mapped out the entire microforest and given each plant a GPS coordinate. And they use drones to measure plant growth, plant volume, and see which species are doing well together and which ones aren't. They also use spider webs to track different animals moving through the microforest.

[Emily Kwong]

Wait, why spider webs?

[Rachel Carlson]

Apparently, they're like nature's DNA swabs.

[Damian Wollett]

Spider webs are kind of a filter for the air. And as animals move through their environment, they're shedding skin cells and metabolic waste that floats in the air that sticks to the spider web. So then we came out here, we collected spiderwebs and washed the DNA off those spider webs, and then got an idea of what are all the animals moving through here within the last 24 hours? 48 hours, using genetic tools.

[Emily Kwong]

So useful are researchers planting the spiders, too, to swap their webs?

[Rachel Carlson]

No, it's just the spiders that naturally show up, and the researchers don't interfere. Aside from studying the webs, Damian says one of his students came up with the idea.

[Emily Kwong]

I always knew spiders would make good scientists.

[Rachel Carlson]

Okay, agree.

[Emily Kwong]

And what have they found out?

[Rachel Carlson]

They've been able to use those webs to figure out what other kinds of animals are hanging out in the microforest, which is especially helpful for ones that are nocturnal or just harder to spot on their walkthroughs.

[Damian Wollett]

We had a barn owl that I've never seen in there, and it's definitely flying through the area at night. And we're picking up a signature of that being here.

[Rachel Carlson]

Bats, too.

[Damian Wollett]

So it just gives us a more full picture of how is this really behaving like a forest. It's not just when we're conveniently here. It's all hours of the day and night.

[Rachel Carlson]

And they also use human community scientists in addition to their spider scientists. Damien's lab developed an app where park visitors can help collect data. And they've had over 150 or so. People use their phones to scan QR codes attached to the plants to help measure their growth.

[Damian Wollett]

We don't use tape measures. We just say, well, how tall are you? And they kind of estimate the height. We look for signs of flowers or seeds or herbivory. And also, is it alive?

[Rachel Carlson]

Damian stood next to a Southern California black walnut tree to show me.

[Damian Wollett]

You can stand next to a few of them, and you can see they're taller than me.

[Rachel Carlson]

How tall are you?

[Damian Wollett]

So I'm just under 6 foot. So that's a little bit higher.

[Rachel Carlson]

Yeah.

[Damian Wollett]

Some of the elderberries down there are over 10 foot, which is incredibly fast when you think about how long it takes for a plant in Southern California.

[Rachel Carlson]

To grow in comparison. He told me he has a black walnut tree in his backyard that's nearly a decade old, but it's not as tall as this one.

[Emily Kwong]

He sounds like a proud parent.

[Rachel Carlson]

He kind of was like, look how.

[Emily Kwong]

Tall my tree grew.

[Rachel Carlson]

He actually hugged the tree at one point, which was maybe my favorite part of the whole day.

[Emily Kwong]

So at the risk of not seeing the forest for the trees, how would you say overall is the health of the totality?

[Rachel Carlson]

It's pretty good. And they've measured it in a few different ways. One way is to look at how many plants have survived since they were first planted. And Damian and Catherine say there's an average of over 89% survivorship for the plants now. Now, which is pretty good. And that's one big measure of success. Another is the plant's ability to exclude weeds without humans like Damien and Catherine having to intervene.

[Emily Kwong]

Oh, how is the forest keeping weeds at bay on its own?

[Rachel Carlson]

So the control plot is filled with weeds, but in the microforest, it's a different story. We're crowding out the space with the plants that we do want so that the plants we don't want really don't have much of a foothold. And that's something that we are already observing. Between year one and year two, it's probably been, like, an 80%, if not more, reduction of weeds inside this space. So that microforest density helps keep weeds at bay. And we know that because scientists are comparing it to the control plot.

[Emily Kwong]

Got it, got it, got it, got it. Is the microforest also contributing to, like, carbon sequestration? You know, removing carbon dioxide from the air.

[Rachel Carlson]

Yeah. And that leads to improved air quality and soil health. And for this microforest, Damian says it's pulling out one metric ton of carbon per year. Dang. His lab expects that to increase to over 50 metric tons of carbon dioxide per year in the next two decades. And that's more than the emissions of 10 SUVs.

[Emily Kwong]

Okay. This microforce is doing its part, plus.

[Damian Wollett]

It'S cooling the neighborhood. It's providing food again, the insects, the wildlife that's here.

[Rachel Carlson]

It also helps bring people into nature. Even in the short time I was with Catherine and Damian, a few people walked by and asked questions about the microforest. They said they love seeing the new plants in the park or asked us what kinds of trees we were looking at and even if they could help.

[Emily Kwong]

For the love of microforest, Rachel Carlson, thank you for bringing this to the show.

[Rachel Carlson]

Yeah, thanks, Emily.

[Emily Kwong]

If you liked this episode, follow us on the NPR app or your podcasting platform of choice. And check out our Nature Quest series, which is inspired by listener questions about the environment and how the planet is changing. If you have a question, send it to us. We'll investigate. Email shortwavepr.org your question and a voice memo and your name and location. This episode was produced by Hannah Chin and edited by our showrunner, Rebecca Ramirez. Tyler Jones, check the facts. Jimmy Keeley was the audio engineer. Beth Donovan is our vice president of podcasting strategy. I'm Emily Kwong. Thank you for listening to Shortwave from npr.

[Narrator/Advertiser]

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